In a fanfic where Harry is raised in Greece, his magic would show a distinct Greek influence. Greek magic has a rich heritage of using symbols and incantations that are deeply rooted in their culture. Harry's spells could incorporate Greek words and phrases, which would give them a different flavor. For example, instead of the typical Latin - based incantations, he might use Greek ones. His magic could also be more community - based, as Greek magic in some traditions involves the participation of the community or family. This would be a contrast to the more individual - focused magic at Hogwarts in the original series. Also, his understanding of magic might be more philosophical, influenced by Greek thinkers and their ideas about the nature of the world and magic.
His magic might be more elemental. Since Greek magic often ties in with the elements like fire, water, earth, and air. He could have an easier time with spells related to these elements compared to other Hogwarts students.
His magic could be more combat - oriented. Jiraiya's ninja background would likely influence Harry to use magic in a more direct and aggressive way in battles, rather than just for defensive or utility purposes like in the original series.
He'd likely be more withdrawn and edgy. Constant exposure to the creepy elements would make him less trusting and more on - guard all the time.
He'd probably be more refined. The Delacours are known for their elegance, so Harry might have better manners and a more sophisticated way of speaking.
His magic could be different in terms of its source. In Harry Potter, magic seems to be more inborn and related to one's heritage and the magic within themselves. In Fairy Tail, magic can be learned and developed in different ways, like through training and guild support. So Harry, raised by Fairy Tail, might have a broader understanding of where his magic comes from. He might see it as something that can be continuously improved and not just as a natural gift. This could lead to him constantly seeking new ways to enhance his magic, perhaps by using Fairy Tail's training methods on traditional Hogwarts spells, which could result in some really unique magical effects.
His magic would probably be more esoteric. Since Zelretch has knowledge of different kinds of magic, Harry could learn spells or abilities that are not part of the normal Hogwarts curriculum. He might be able to manipulate time or space in ways that other wizards can't.
Well, since Moody is a very vigilant and somewhat paranoid character, Harry would be more observant. He would constantly be on the lookout for danger, like Moody does. His sense of humor might also be a bit darker, influenced by Moody's experiences in the wizarding wars. He might not be as quick to make friends, as he would be more focused on who could be a potential threat. Also, his view of authority might be different. Instead of always looking up to Dumbledore, he might question authority more often, as Moody is a bit of a maverick in his own right.
If house - elves raised him, Harry would be extremely humble and have a strong sense of service. He wouldn't have the same pride as he does in the original series. He would also be very good at taking care of details and might be more of a behind - the - scenes helper at Hogwarts rather than the center of attention all the time.
If Harry Potter was raised in Greece, he might grow up with a deep connection to Greek mythology. He could learn about ancient magic that is intertwined with Greek gods and monsters. His Hogwarts experience would be different as he'd bring a unique cultural perspective, perhaps even introducing some Greek magical concepts to his classmates.
His magic might be more aggressive. Growing up with the Dark Lord, he would be taught to use magic for more forceful and often cruel means. For instance, instead of using a simple Stunning Spell like in the original, he could be using more dangerous and unforgivable - like spells without hesitation.
Harry's magic could be stronger. Dorea's influence and knowledge of magic could have allowed Harry to tap into his magic potential more easily. Maybe he would be able to perform advanced spells earlier. Also, his magic might have a different 'flavor' so to speak. Since Dorea comes from a different magical background than the Dursleys, Harry's magic could be more attuned to the traditional wizarding ways of magic use.